The short version of Semax fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-09-28. Anything still debated is marked as such rather than presented as settled.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues correspond to the ACTH(4-10) fragment, while the terminal Pro-Gly-Pro extension was added to improve metabolic stability. Its molecular formula is C37H51N9O10S and its monoisotopic mass is approximately 813.9 Da. The compound is classified as a peptide research chemical and as a registered pharmaceutical product in Russia, but it does not hold marketing approval in the European Union or the United States. Naming conventions vary across supplier catalogs.
Development of the compound took place in the Soviet Union during the 1980s, largely through peptide research groups affiliated with the Shemyakin-Ovchinnikov Institute and Moscow State University. Investigators screened fragments of adrenocorticotropic hormone for activity on the central nervous system while attempting to separate cognitive effects from hormonal ones. The shortened sequence was selected because it retained behavioral activity in animal models without stimulating corticosteroid release. Early publications described the molecule as an ACTH(4-10) analog.
溶液状态的稳定性明显低于冻干粉。肽类在水溶液中可能经历水解、氧化与聚集，其中甲硫氨酸和天冬酰胺等残基常是敏感位点。Semax 含有甲硫氨酸，因此氧化风险相对突出。工作液一般主张现配现用，或冷藏并在数日内用尽。缓冲液种类、pH 和离子强度都会影响降解速率，而关于最佳条件的公开数据并不统一。
常规纯度与身份确认依赖反相高效液相色谱，并辅以质谱测定分子量。氨基酸组成分析可用于验证序列构成，肽图分析则能进一步定位修饰或降解产物。杂质谱通常关注缺失序列肽、截短片段和氧化产物。不同方法的检出限并不相同，因此各实验室报告的纯度数值不宜直接横向比较。
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Seven-residue peptide |
| Molecular mass | 813.9 Da | Monoisotopic value |
| Appearance | White to off-white powder | Lyophilized form |
| Solubility | Freely soluble in water | Also soluble in saline and polar solvents |
| Storage (dry) | -20 °C or lower | Desiccated, protected from light |
Terminology around the compound varies by source. It appears in catalogues and papers as Semax, as the heptapeptide ACTH(4-7)-Pro-Gly-Pro, and under various alphanumeric laboratory codes used by individual suppliers. These names refer to the same sequence but may imply different salt forms, purity grades, or counter-ions. Peptide databases usually list the free base mass, while product descriptions sometimes report acetate or trifluoroacetate salts with a different formula weight. Because naming conventions for research peptides are not standardised across vendors, checking the declared sequence and measured mass is more reliable than relying on a trade name alone.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its design combines the ACTH(4-7) core fragment with a C-terminal Pro-Gly-Pro extension, a modification intended to improve stability and prolong activity. The molecule is hydrophilic, carries no lipid chains or glycosylation, and has a theoretical mass just over 810 daltons in its free form. All seven residues are proteinogenic amino acids, so no non-natural building blocks appear in the backbone. A free N-terminal methionine and C-terminal proline define the unmodified parent peptide.
The compound was developed during the 1980s at the Institute of Molecular Genetics in Moscow as part of research on fragments of adrenocorticotropic hormone. Early work examined short ACTH-derived sequences that retained neurotrophic effects while lacking the endocrine activity of the full hormone. Semax entered clinical use in Russia during the 1990s, where it received registration for several neurological indications. Outside that region it remained primarily a laboratory research material rather than an approved therapeutic. English-language literature on it grew more slowly and frequently cited the original Russian studies.
稳定性主要由水解与氧化两条路径支配。肽键在中性或弱酸性条件下相对稳定，遇到强碱或长时间高温则明显断裂；甲硫氨酸侧链容易被氧化成亚砜，使主峰前移并拉低实际含量。金属离子、光照和反复冻融会进一步促进降解或聚集。冻干粉在低温避光条件下可存放较长时间，配制后的水溶液通常需要冷藏并尽快用完。
纯度评估以反相高效液相色谱为主，通过主峰面积百分比给出粗略结果，再配合电喷雾质谱核对分子量。氨基酸分析可验证组成比例，手性色谱或毛细管电泳用于检查残基构型。常见杂质包括缺失序列的短肽、氧化产物与二聚体。由于多数市售品不附带完整检验报告，独立第三方检测常被用来核实标称值。
Grafting, in the context of polymer chemistry, refers to the addition of polymer chains onto a surface. In the so-called 'grafting onto' mechanism, a polymer chain adsorbs onto a surface out of solution. In the more extensive 'grafting from' mechanism, a polymer chain is initiated and propagated at the surface. Because pre-polymerized chains used in the 'grafting onto' method have a thermodynamically favored conformation in solution (an equilibrium hydrodynamic volume), their adsorption density is self-limiting. The radius of gyration of the polymer therefore is the limiting factor in the number of polymer chains that can reach the surface and adhere. The 'grafting from' technique circumvents this phenomenon and allows for greater grafting densities. The processes of grafting "onto", "from", and "through" are all different ways to alter the chemical reactivity of the surface they attach with. Grafting onto allows a preformed polymer, generally in a "mushroom regime", to adhere to the surface of either a droplet or bead in solution. Due to the larger volume of the coiled polymer and the steric hindrance this causes, the grafting density is lower for 'onto' in comparison to 'grafting from'. The surface of the bead is wetted by the polymer and the interaction in the solution caused the polymer to become more flexible. The 'extended conformation' of the polymer grafted, or polymerized, from the surface of the bead means that the monomer must be in the solution and there for lyophilic.
CPA, also known as 1α,2α-methylene-6-chloro-17α-acetoxy-δ6-progesterone or as 1α,2α-methylene-6-chloro-17α-hydroxypregna-4,6-diene-3,20-dione acetate, is a synthetic pregnane steroid and an acetylated derivative of 17α-hydroxyprogesterone. It is structurally related to other 17α-hydroxyprogesterone derivatives such as chlormadinone acetate, hydroxyprogesterone caproate, medroxyprogesterone acetate, and megestrol acetate.
=== Design of scientific investigations === Aarons has defined pharmacokinetics (PK) as the study of the complex chain of events that links a dose of drugs administered to a patient and the expected effect or response. PK is based on analysing the concentration of drugs and tracking how they are absorbed, distributed, metabolised and excreted within the patient. Some of his work has involved using optimal design theory to explore what makes a successful scientific investigation for pharmacokinetic studies and has said that this "involves the selection and a careful balance of a number of design factors, including the number and location of measurement times and the number of subjects to include in the study." According to Aarons, population pharmacokinetics studies which focus on what happens to the substances administered to a patient would need specific design factors that apply "statistical experimental design principles to non-linear population pharmacokinetic models." A later paper co-authored by Aarons, reviews the different approaches to optimal design of population pharmacokinetic and pharmacodynamic experiments and notes that some of the options may raise concerns at to their practicality. The paper did, however, conclude "that as the awareness about the benefits of this approach increases, more people will embrace it and ultimately will lead to more efficient population pharmacokinetic and pharmacodynamic experiments."
Insulin signal transduction Cytoskeleton assembly Nerve guidance (epsin) Intracellular calcium (Ca2+) concentration control Cell membrane potential maintenance Breakdown of fats Gene expression In one important family of pathways, phosphatidylinositol 4,5-bisphosphate (PIP2) is stored in cellular membranes until it is released by any of a number of signalling proteins and transformed into various secondary messengers, for example diacylglycerol and inositol trisphosphate. 'myo-Inositol has very low toxicity, with a reported LD50 10,000 mg/kg body weight (oral) in rats.
Sources: en.wikipedia.org
The targets were said to have been Zdeněk Hřib, the mayor of Prague (capital of the Czech Republic), who was involved in renaming a square in Prague, "Pod Kaštany", where the Russian embassy is situated, to the Square of Boris Nemtsov, an opposition politician assassinated in the Kremlin in 2015; Ondřej Kolář, the mayor of Prague 6 municipal district, who was involved in removing the controversial statue to the Soviet-era Marshal Konev; and Pavel Novotný, the mayor of Prague's southwestern Řeporyje district. They all received police protection. Czech president Miloš Zeman later described the police protection of Zdeněk Hřib as an attempt by an insignificant politician to gain attention. Zeman also confused ricin with non-poisonous laxative castor oil. In 2018 and 2023 German police thwarted attempted ricin attacks, after tip-offs believed to have come from the US FBI. In 2025, security agencies in the Indian state of Gujarat arrested three Muslim men allegedly plotting a terrorist attack using ricin.
Selective estrogen receptor modulators (SERMs) are an important class of hormonal therapy agents which act as antagonists of the estrogen receptor and are used primarily for the treatment and chemoprevention of breast cancer. Some members of this family, such as tamoxifen, are actually partial agonists, which can actually increase estrogen receptor signalling in some tissues, such as the endometrium. Tamoxifen is currently first-line treatment for nearly all pre-menopausal women with hormone receptor-positive breast cancer. Raloxifene is another partial agonist SERM which does not seem to promote endometrial cancer, and is used primarily for chemoprevention of breast cancer in high-risk individuals, as well as to prevent osteoporosis. Toremifene and fulvestrant are SERMs with little or no agonist activity, and are used for treatment of metastatic breast cancer.
The Media Act of 1988 facilitated several changes to NOS and the broadcasting system. The Services Department, which was made up of the technical, broadcast, and transmission facilities of the NOS, was privatised, which meant the broadcasting associations were required to pay to use the facilities. The Nederlands Omroepproduktie Bedrijf (Netherlands Broadcast Production Company; NOB) consisted of those facilities, mainly based in Media Park in Hilversum. The Media Act also required broadcasting association members to take up positions on the NOS Board of Directors. A new government commission oversaw content and financial matters, as well as admitting potential new broadcasting associations.
== In vivo vs In vitro == In vivo staining (also called vital staining or intravital staining) is the process of dyeing living tissues. By causing certain cells or structures to take on contrasting colours, their form (morphology) or position within a cell or tissue can be readily seen and studied. The usual purpose is to reveal cytological details that might otherwise not be apparent; however, staining can also reveal where certain chemicals or specific chemical reactions are taking place within cells or tissues. In vitro staining involves colouring cells or structures that have been removed from their biological context. Certain stains are often combined to reveal more details and features than a single stain alone. Combined with specific protocols for fixation and sample preparation, scientists and physicians can use these standard techniques as consistent, repeatable diagnostic tools. A counterstain is stain that makes cells or structures more visible, when not completely visible with the principal stain.
The Chinese cobra (Naja atra) is a highly venomous member of the true cobras (genus Naja). Its venom consists mainly of postsynaptic neurotoxins and cardiotoxins. Four cardiotoxin-analogues I, II, III, and IV, account for about 54% of the dry weight of the crude venom and have cytotoxic properties. The LD50 values of its venom in mice are 0.29 mg/kg IV, and 0.29 – 0.53 mg/kg SC. The average venom yield from a snake of this species kept at a snake farm was about 250.8 mg (80 mg dry weight). According to Minton (1974), this cobra has a venom yield range of 150 to 200 mg (dry weight). Brown listed a venom yield of 184 mg (dry weight). It is one of the most prevalent venomous snakes in mainland China and Taiwan, which has caused many snakebite incidents to humans.
Sources: en.wikipedia.org
It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.
The extension was introduced to slow enzymatic breakdown of the peptide in biological systems. Natural ACTH fragments are degraded rapidly by peptidases. Adding the tripeptide was intended to extend the window during which the molecule remains intact.
Most published work consists of animal experiments conducted in a small number of laboratories. Human data are limited in number and size. Whether the observed effects translate into reliable clinical benefit is still unresolved.
一般不建议常温长期保存。多数说明指向 -20 °C 冷冻避光。常温运输通常被视为短期可接受，但会加快降解风险。